Vortex state microwave resistivity in Tl-2212 thin films

We present measurements of the field induced changes in the 47 GHz complex resistivity, $\Delta \tilde \rho(H,T)$, in Tl$_{2}$Ba$_{2}$CaCu$_{2}$O$_{8+x}$ (TBCCO) thin films with $T_{c}\simeq$ 105 K, prepared on CeO$_{2}$ buffered sapphire substrates. At low fields ($\mu_{0}H<$10 mT) a very small irreversible feature is present, suggesting a little role of intergranular phenomena. Above that level $\Delta \tilde \rho(H,T)$ exhibits a superlinear dependence with the field, as opposed to the expected (at high frequencies) quasilinear behaviour. We observe a crossover between predominantly imaginary to predominantly real (dissipative) response with increasing temperature and/or field. In addition, we find the clear scaling property $\Delta \tilde \rho(H,T)=\Delta \tilde \rho[H/H^{*}(T)]$, where the scaling field $H^{*}(T)$ maps closely the melting field measured in single crystals. We discuss our microwave results in terms of loss of flux lines rigidity.Comment: 8 pages, 3 figures, proceedings of 9th HTSHFF, accepted for publication on J. Supercon

Scaling of the microwave magneto-impedance in Tl2_2Ba2_2CaCu2_2O8+δ_{8+\delta} thin films

We present measurements of the magnetic field-induced microwave complex resistivity changes at 47 GHz in Tl$_2$Ba$_2$CaCu$_2$O$_{8+\delta}$ (TBCCO) thin films, in the ranges 58 K$<T<T_{c}$ and 0$<\mu_{0}H<$0.8 T. The large imaginary part $\Delta\rho_{2}(H)$ points to strong elastic response, but the data are not easily reconciled with a rigid vortex model. We find that, over a wide range of temperatures, all the pairs of curves $\Delta\rho_{1}(H)$ and $\Delta\rho_{2}(H)$ can be collapsed on a pair of scaling curves $\Delta\rho_{1}[H/H^{*}(T)]$, $\Delta\rho_{2}[H/H^{*}(T)]$, with the same scaling field $H^{*}(T)$. We argue that $H^{*}(T)$ is related to the loss of vortex rigidity due to a vortex transformation.Comment: Two printed pages, Proceedings of M2S (Dresden, 2006), to appear in Physica

Association of mid-infrared solar plages with Calcium K line emissions and magnetic structures

Solar mid-IR observations in the 8-15 micrometer band continuum with moderate angular resolution (18 arcseconds) reveal the presence of bright structures surrounding sunspots. These plage-like features present good association with calcium CaII K1v plages and active region magnetograms. We describe a new optical setup with reflecting mirrors to produce solar images on the focal plane array of uncooled bolometers of a commercial camera preceded by germanium optics. First observations of a sunspot on September 11, 2006 show a mid-IR continuum plage exhibiting spatial distribution closely associated with CaII K1v line plage and magnetogram structures. The mid-IR continuum bright plage is about 140 K hotter than the neighboring photospheric regions, consistent with hot plasma confined by the magnetic spatial structures in and above the active regionComment: 5 pages, 4 figures. Accepted by PAS

Celiac Disease and Pediatric Type 1 Diabetes: Diagnostic and Treatment Dilemmas

Despite the advent of sensitive and specific serologic testing, routine screening for celiac disease (CD) in diabetic populations may not be universal practice, and many clinicians struggle to find the optimal approach to managing CD in pediatric Type 1 diabetes (T1D) patients. While some clinicians advocate screening for CD in all patients with T1D, others are unsure whether this is warranted. The diagnosis of patients who present with symptomatic CD, including malabsorption and obvious pathology upon biopsy, remains straightforward, with improvements noted on a gluten-free diet. Many patients identified by screening, however, tend to be asymptomatic. Evidence is inconclusive as to whether the benefits of screening and potentially treating asymptomatic individuals outweigh the harms of managing a population already burdened with a serious illness. This review focuses on current knowledge of CD in children and youth with T1D, highlighting important elements of the disease's pathophysiology, epidemiology, clinical presentation, and diagnostic challenges

Nonlinear AC resistivity in s-wave and d-wave disordered granular superconductors

We model s-wave and d-wave disordered granular superconductors with a three-dimensional lattice of randomly distributed Josephson junctions with finite self-inductance. The nonlinear ac resistivity of these systems was calculated using Langevin dynamical equations. The current amplitude dependence of the nonlinear resistivity at the peak position is found to be a power law characterized by exponent $\alpha$. The later is not universal but depends on the self-inductance and current regimes. In the weak current regime $\alpha$ is independent of the self-inductance and equal to 0.5 or both of s- and d-wave materials. In the strong current regime this exponent depends on the screening. We find $\alpha \approx 1$ for some interval of inductance which agrees with the experimental finding for d-wave ceramic superconductors.Comment: 4 pages, 5 figures, to appear in Phys. Rev. Let

Nível de energia metabolizável aparente sobre o desempenho zootécnico de frangos de corte.

O milho é o principal ingrediente energético utilizado nas rações brasileiras para frango de corte. O frango de corte macho de desempenho superior necessita segundo Rostagno (1) cerca de 3.150 e 3.200 kcal/kg no período de 22 à 33 e 34 à 42 dias de idade, respectivamente. Para atender essa demanda energética óleos e gordura são incluídos nas formulações. O objetivo do trabalho foi avaliar o requerimento energia metabolizável aparente (EMA) de frangos de corte machos consumindo dieta peletizada/triturada de 21 a 42 dias com base nas variáveis de desempenho zootécnico